Transmission and scanning electron microscopic study peripheral blood immunoblasts of a splenectomized patient.

A 32-year-old patient, known to suffer from paroxysmal cold hemoglobinuria, developed a marked immunoblastic reaction in the peripheral blood and bone marrow following pneumonia and pericarditis, most probably of viral origin. Transmission electron microscopic examination showed cells with irregular nucleus, scarce heterochromatin and well-developed Golgi formation. The surface ultrastructure examined with a scanning electron microscope was characterized by the presence of ridges, ruffles and blebs on the cell membrane. Since the patient underwent splenectomy 23 years prior, the possible role of the spleen in the removal of the immunoblasts from the peripheral blood of patients with viral infections is discussed.